From 6e790552fe7a1f34e584160ceef051b6f66b7ce4 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Fri, 15 Apr 2022 17:34:19 +0100
Subject: libdislocator, new option to name an anonymous address range. For
 performance matter tough, disabled by default.

---
 utils/libdislocator/libdislocator.so.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'utils/libdislocator/libdislocator.so.c')

diff --git a/utils/libdislocator/libdislocator.so.c b/utils/libdislocator/libdislocator.so.c
index 103da9d5..72fafa4b 100644
--- a/utils/libdislocator/libdislocator.so.c
+++ b/utils/libdislocator/libdislocator.so.c
@@ -39,6 +39,7 @@
 
 #if (defined(__linux__) && !defined(__ANDROID__)) || defined(__HAIKU__)
   #include <unistd.h>
+  #include <sys/prctl.h>
   #ifdef __linux__
     #include <sys/syscall.h>
     #include <malloc.h>
@@ -66,6 +67,10 @@
       } while (0)
 
   #endif
+  #ifndef PR_SET_VMA
+    #define PR_SET_VMA 0x53564d41
+    #define PR_SET_VMA_ANON_NAME 0
+  #endif
 #endif
 
 #include "config.h"
@@ -251,6 +256,19 @@ static void *__dislocator_alloc(size_t len) {
 
   }
 
+#if defined(USENAMEDPAGE)
+#if defined(__linux__)
+  // in the /proc/<pid>/maps file, the anonymous page appears as
+  // `<start>-<end> ---p 00000000 00:00 0 [anon:libdislocator]`
+  if (prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME,
+    (unsigned long)ret, tlen, (unsigned long)"libdislocator") < 0) {
+
+    DEBUGF("prctl() failed");
+
+  }
+#endif
+#endif
+
   /* Set PROT_NONE on the last page. */
 
   if (mprotect(ret + PG_COUNT(rlen + 8) * PAGE_SIZE, PAGE_SIZE, PROT_NONE))
-- 
cgit 1.4.1